Biosketch:
John Ham, PhD, Professor of Economics, joined the Department of Economics at Ohio State University in 2000. Previously he was on faculty at the University of Toronto and University of Pittsburgh. He is a Faculty Research Associate in the Center for Human Resource Research at the Ohio State University and a Research Fellow in the William Davidson Institute at University of Michigan Business School. He serves on the editorial board of Demography, Journal of Econometrics, Labour Economics, and the Pacific Economic Review. He received his PhD in economics in 1980 at Princeton University specializing in labor economics. His current research interests have shifted towards health economics and empirical microeconomics. Presently he is investigating the use of various econometric estimators and survey design in the analysis of data from laboratory experiments with J. Kagel and S. Lehrer. In the area of health economics he is collaborating with L. Shore Sheppard on a variety of projects using data from the Survey of Income and Program Participation. In one project, they are studying the labor market dynamics of disadvantaged women and the effect of the expansion of medical insurance over the last ten years on transitions out of welfare. They are also looking at the dynamics of health insurance coverage of children and have recently received an NIH grant to continue their work in these areas. Finally, he has a strong interest in the martial arts and holds a brown belt in Wu-Shuryu-Do Karate.

Abstract:Increased availability of public health insurance for children has led to two potentially contradictory concerns for public policy: that expanded availability of public insurance may lead families to decline private insurance and that additional public coverage may not reach many uninsured children. To examine these concerns we use data from the 1987-1993 Surveys of Income and Program Participation and estimate dynamic models of insurance choice. Dynamic models permit the separate examination of transitions between three insurance states: i) public insurance, ii) private insurance; and iii) no insurance. This extends earlier work which has focused almost exclusively on adults and tends to examine transitions between only two states. We find that impact of expanded Medicaid eligibility on income limits are significantly negative in the: i) transition rate from private to no insurance and ii) transition rate from public to no insurance. The income limits significantly increase: i) the transition rate from private to public insurance and ii) the transition rate from no insurance to public insurance. Finally, the income limits does not affect transitions from public to private insurance. The results suggest that crowding out occurs through transition rates from private to public insurance and not from public to private insurance.